Social preference in rats

Rats were given repeated choices between social and nonsocial outcomes, and between familiar and unfamiliar social outcomes. Lever presses on either of 2 levers in the middle chamber of a 3-chamber apparatus opened a door adjacent to the lever, permitting 45-s access to social interaction with the rat in the chosen side chamber. In Experiment 1, rats preferred (a) social over nonsocial options, choosing their cagemate rat over an empty chamber, and (b) an unfamiliar over a familiar rat, choosing a non-cagemate over their cagemate. These findings were replicated in Experiment 2 with 2 different non-cagemate rats. Rats preferred both non-cagemate rats to a similar degree when pitted against their cagemate, but were indifferent when the 2 non-cagemates were pitted against each other. Similar preference for social over nonsocial and non-cagemate over cagemate was seen in Experiment 3, with new non-cagemate rats introduced after every third session. Response rates (for both cagemate and non-cagemate rats) were elevated under conditions of nonsocial (isolated) housing compared to conditions of social (paired) housing, demonstrating a social deprivation effect. Together, the experiments contribute to an experimental analysis of social preference within a social reinforcement framework, drawing on methods with proven efficacy in the analysis of reinforcement more generally.     

Plasticity of the association between visual space and action space in a blind-walking task

Many experiments have shown that a brief visual preview provides sufficient information to complete certain kinds of movements (reaching, grasping, and walking) with high precision. This suggests that participants must possess a calibration between visual target location and the kinaesthetic, proprioceptive, and/or vestibular stimulation generated during movement towards the target. We investigated the properties of this calibration using a cue-conflict paradigm in which participants were trained with mismatched locomotor and visual input. After training, participants were presented with visual targets and were asked to either walk to them or locate them in a spatial updating task. Our results showed that the training was sufficient to produce significant, systematic miscalibrations of the association between visual space and action space. These findings suggest that the association between action space and visual space is modifiable by experience. This plasticity could be either due to modification of a simple, task-specific sensory motor association or it could reflect a change in the gain of a path integration signal or a reorganisation of the relationship between perceived space and action space. We suggest further experiments that might help to distinguish between these possibilities.     

Work‐Group Membership (In)Stability and Survivors' Reactions to Organizational Downsizing1

This longitudinal panel study investigated the interactive effect of work‐group membership stability and time on survivors' reactions to organizational downsizing. The participants were 159 nonmanagement employees of a federal government department. Survivors in moderate‐change work groups did not react more negatively to the downsizing. In fact, they reported a significant increase in job satisfaction, job security, job performance, and employee morale. Survivors who changed to different work groups expressed the least positive attitudes in the initial phase of the downsizing, but the most positive attitudes at the completion of the downsizing. Work‐group membership (in)stability was more likely to affect survivors' reactions to various aspects of their job over time than factors related to the work group itself.     

Past experience influences object representation in working memory

The nature of object representation in working memory is vital to establishing the capacity of working memory, which in turn shapes the limits of visual cognition and awareness. Although current theories discuss whether representations in working memory are feature-based or object-based, no theory has considered the role of past experience. However, work with humans and non-human primates suggests that once participants learn which features are important for category membership, these diagnostic features become more salient than non-diagnostic features in long-term memory and object recognition. Critically, the brain areas involved in this diagnosticity effect are also recruited during working memory tasks. We report two experiments testing whether a diagnosticity effect exists in working memory; and whether it is present when visual information is encoded into working memory, or if it is the result of maintenance within working memory. Results showed a diagnosticity effect which was present at encoding. Maintenance did not influence the nature of object representation in working memory. These findings show that the meaning we glean from our past experience has a profound influence on the nature of object representation in working memory.     

Colored photisms prevent object-substitution masking in digit-color synesthesia

For C, a digit-color synesthete, viewing a digit elicits a photism (an experience of a highly specific color), which is perceived as externally projected onto the digit. We used an object substitution paradigm to demonstrate the influence of C's photisms on her perception of digits. Object substitution refers to a form of masking that depends upon two critical factors: attention must be taxed (e.g., distributed among numerous distracters), and the mask must remain on-screen for a sufficient duration after the target has been removed. Results showed that for C, even under conditions that produced maximal object substitution in control participants, her endogenous coloring of target digits prevented object substitution. Thus, the present study clearly showed that C's photisms influence her ability to detect digits.     

Spiking Phineas Gage: a neurocomputational theory of cognitive-affective integration in decision making

The authors present a neurological theory of how cognitive information and emotional information are integrated in the nucleus accumbens during effective decision making. They describe how the nucleus accumbens acts as a gateway to integrate cognitive information from the ventromedial prefrontal cortex and the hippocampus with emotional information from the amygdala. The authors have modeled this integration by a network of spiking artificial neurons organized into separate areas and used this computational model to simulate 2 kinds of cognitive-affective integration. The model simulates successful performance by people with normal cognitive-affective integration. The model also simulates the historical case of Phineas Gage as well as subsequent patients whose ability to make decisions became impeded by damage to the ventromedial prefrontal cortex.     

Criminogenic Thinking Mediates the Relation Between Violent Media Exposure and Aggression

For decades researchers have been exploring the connection between exposure to violent media and aggression in adolescents. In this study, we hypothesized that criminogenic thinking would mediate the relationship between violent media exposure and aggression. A sample of 382 undergraduate students completed questionnaires regarding exposure to violent media during their adolescent years, and their current endorsement of criminogenic thinking and level of aggression. Results indicated that criminogenic thinking patterns did, in fact, mediate the relationships between exposure to various forms of violent media and aggression. The implications of these findings toward a better understanding of the relationship between violent media exposure and aggressive behavior are discussed.     

The relationship between plaintiff gender and just cause determination in Canadian dismissal cases

Widespread concern has been expressed recently over the differential treatment of women by the courts and various arbitration and adjudication proceedings. Based on data obtained by content analysing 367 Canadian dismissal cases from 1980 to 1993, this study examines the relationship between the plaintiff's gender and the court's ruling regarding the existence of just cause for termination. The results indicate that female plaintiffs are more likely than men to succeed in their court action. However, in comparison with their representation in the Canadian workforce, a relatively small percentage of women are plaintiffs in wrongful dismissal actions. Possible explanations for the study's findings are discussed.Funding for this study was provided by a Saint Mary's University Senate Research Grant to the first author. The very capable research assistance of Nancy Canavan and Jane MacNeil is gratefully acknowledged.     

Culture, memory, and the self: An analysis of the personal and collective self in long-term memory

We used a memory paradigm to test whether the nature of representations of the self within long-term memory differed as a function of cultural background. In Western samples words encoded in relation to the self are typically remembered better, and Euro-Canadian participants here showed this standard self-reference effect. However, Asian-Canadian participants were slower to recognize personal traits (as opposed to collective traits) when these traits had been encoded in reference to the self, suggesting a more elaborate representation of the collective self than the personal self in long-term memory. Further, memory was actually inhibited for Asian-Canadians when personal traits were encoded in reference to the self (vs. encoded with other referents). Differences in long-term memory trace strength for self-related data may emerge even as differences in the working self do not, and implications of this difference are discussed.